“(i) input tax is directly attributable to a given output if it has a “direct and immediate” link with that output (referred to as “ the BLP ” test); (ii) that test has been formulated in different ways over the years, for example whether the input is a “cost component” of the output; or whether the input is “essential” to the particular output. Such formulations are the same in substance as the “direct and immediate link” test; (iii) the application of the BLP test is a matter of objective analysis as to how particular inputs are used and is not dependant upon establishing what is the ultimate aim pursued by the taxable person. It requires more than mere commercial links between transactions, or a “but for” approach; (iv) the test is not one of identifying what is the transaction with which the input has the most direct and immediate link, but whether there is a sufficient direct and immediate link with a taxable economic activity; and (v) the test is one of mixed fact and law, and is therefore amenable to review in the higher courts, albeit the test is fact sensitive.”